From 339bf98ffc6a8d8eb16fc532ac57ffbced2f8a68 Mon Sep 17 00:00:00 2001 From: Thomas Graf Date: Fri, 10 Nov 2006 14:10:15 -0800 Subject: [NETLINK]: Do precise netlink message allocations where possible Account for the netlink message header size directly in nlmsg_new() instead of relying on the caller calculate it correctly. Replaces error handling of message construction functions when constructing notifications with bug traps since a failure implies a bug in calculating the size of the skb. Signed-off-by: Thomas Graf Acked-by: Paul Moore Signed-off-by: David S. Miller --- net/core/fib_rules.c | 24 +++++++++++++++++++----- net/core/neighbour.c | 17 ++++++++++++----- net/core/rtnetlink.c | 39 ++++++++++++++++++++++++++------------- 3 files changed, 57 insertions(+), 23 deletions(-) (limited to 'net/core') diff --git a/net/core/fib_rules.c b/net/core/fib_rules.c index 4148e27..1df6cd45 100644 --- a/net/core/fib_rules.c +++ b/net/core/fib_rules.c @@ -306,6 +306,22 @@ errout: return err; } +static inline size_t fib_rule_nlmsg_size(struct fib_rules_ops *ops, + struct fib_rule *rule) +{ + size_t payload = NLMSG_ALIGN(sizeof(struct fib_rule_hdr)) + + nla_total_size(IFNAMSIZ) /* FRA_IFNAME */ + + nla_total_size(4) /* FRA_PRIORITY */ + + nla_total_size(4) /* FRA_TABLE */ + + nla_total_size(4) /* FRA_FWMARK */ + + nla_total_size(4); /* FRA_FWMASK */ + + if (ops->nlmsg_payload) + payload += ops->nlmsg_payload(rule); + + return payload; +} + static int fib_nl_fill_rule(struct sk_buff *skb, struct fib_rule *rule, u32 pid, u32 seq, int type, int flags, struct fib_rules_ops *ops) @@ -384,15 +400,13 @@ static void notify_rule_change(int event, struct fib_rule *rule, struct sk_buff *skb; int err = -ENOBUFS; - skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL); + skb = nlmsg_new(fib_rule_nlmsg_size(ops, rule), GFP_KERNEL); if (skb == NULL) goto errout; err = fib_nl_fill_rule(skb, rule, pid, nlh->nlmsg_seq, event, 0, ops); - if (err < 0) { - kfree_skb(skb); - goto errout; - } + /* failure implies BUG in fib_rule_nlmsg_size() */ + BUG_ON(err < 0); err = rtnl_notify(skb, pid, ops->nlgroup, nlh, GFP_KERNEL); errout: diff --git a/net/core/neighbour.c b/net/core/neighbour.c index b4b4783..0e097ba 100644 --- a/net/core/neighbour.c +++ b/net/core/neighbour.c @@ -2410,20 +2410,27 @@ static struct file_operations neigh_stat_seq_fops = { #endif /* CONFIG_PROC_FS */ #ifdef CONFIG_ARPD +static inline size_t neigh_nlmsg_size(void) +{ + return NLMSG_ALIGN(sizeof(struct ndmsg)) + + nla_total_size(MAX_ADDR_LEN) /* NDA_DST */ + + nla_total_size(MAX_ADDR_LEN) /* NDA_LLADDR */ + + nla_total_size(sizeof(struct nda_cacheinfo)) + + nla_total_size(4); /* NDA_PROBES */ +} + static void __neigh_notify(struct neighbour *n, int type, int flags) { struct sk_buff *skb; int err = -ENOBUFS; - skb = nlmsg_new(NLMSG_GOODSIZE, GFP_ATOMIC); + skb = nlmsg_new(neigh_nlmsg_size(), GFP_ATOMIC); if (skb == NULL) goto errout; err = neigh_fill_info(skb, n, 0, 0, type, flags); - if (err < 0) { - kfree_skb(skb); - goto errout; - } + /* failure implies BUG in neigh_nlmsg_size() */ + BUG_ON(err < 0); err = rtnl_notify(skb, 0, RTNLGRP_NEIGH, NULL, GFP_ATOMIC); errout: diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 02f3c79..50d6cb4 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -273,6 +273,25 @@ static void copy_rtnl_link_stats(struct rtnl_link_stats *a, a->tx_compressed = b->tx_compressed; }; +static inline size_t if_nlmsg_size(int iwbuflen) +{ + return NLMSG_ALIGN(sizeof(struct ifinfomsg)) + + nla_total_size(IFNAMSIZ) /* IFLA_IFNAME */ + + nla_total_size(IFNAMSIZ) /* IFLA_QDISC */ + + nla_total_size(sizeof(struct rtnl_link_ifmap)) + + nla_total_size(sizeof(struct rtnl_link_stats)) + + nla_total_size(MAX_ADDR_LEN) /* IFLA_ADDRESS */ + + nla_total_size(MAX_ADDR_LEN) /* IFLA_BROADCAST */ + + nla_total_size(4) /* IFLA_TXQLEN */ + + nla_total_size(4) /* IFLA_WEIGHT */ + + nla_total_size(4) /* IFLA_MTU */ + + nla_total_size(4) /* IFLA_LINK */ + + nla_total_size(4) /* IFLA_MASTER */ + + nla_total_size(1) /* IFLA_OPERSTATE */ + + nla_total_size(1) /* IFLA_LINKMODE */ + + nla_total_size(iwbuflen); +} + static int rtnl_fill_ifinfo(struct sk_buff *skb, struct net_device *dev, void *iwbuf, int iwbuflen, int type, u32 pid, u32 seq, u32 change, unsigned int flags) @@ -558,7 +577,7 @@ static int rtnl_getlink(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg) struct sk_buff *nskb; char *iw_buf = NULL, *iw = NULL; int iw_buf_len = 0; - int err, payload; + int err; err = nlmsg_parse(nlh, sizeof(*ifm), tb, IFLA_MAX, ifla_policy); if (err < 0) @@ -587,9 +606,7 @@ static int rtnl_getlink(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg) } #endif /* CONFIG_NET_WIRELESS_RTNETLINK */ - payload = NLMSG_ALIGN(sizeof(struct ifinfomsg) + - nla_total_size(iw_buf_len)); - nskb = nlmsg_new(nlmsg_total_size(payload), GFP_KERNEL); + nskb = nlmsg_new(if_nlmsg_size(iw_buf_len), GFP_KERNEL); if (nskb == NULL) { err = -ENOBUFS; goto errout; @@ -597,10 +614,8 @@ static int rtnl_getlink(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg) err = rtnl_fill_ifinfo(nskb, dev, iw, iw_buf_len, RTM_NEWLINK, NETLINK_CB(skb).pid, nlh->nlmsg_seq, 0, 0); - if (err <= 0) { - kfree_skb(nskb); - goto errout; - } + /* failure impilies BUG in if_nlmsg_size or wireless_rtnetlink_get */ + BUG_ON(err < 0); err = rtnl_unicast(nskb, NETLINK_CB(skb).pid); errout: @@ -639,15 +654,13 @@ void rtmsg_ifinfo(int type, struct net_device *dev, unsigned change) struct sk_buff *skb; int err = -ENOBUFS; - skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL); + skb = nlmsg_new(if_nlmsg_size(0), GFP_KERNEL); if (skb == NULL) goto errout; err = rtnl_fill_ifinfo(skb, dev, NULL, 0, type, 0, 0, change, 0); - if (err < 0) { - kfree_skb(skb); - goto errout; - } + /* failure implies BUG in if_nlmsg_size() */ + BUG_ON(err < 0); err = rtnl_notify(skb, 0, RTNLGRP_LINK, NULL, GFP_KERNEL); errout: -- cgit v1.1